"Whether you have dementia or not, you need to hear," said Ronna Fisher, audiologist and founder and president of Hearing Health Center in Chicago and three suburbs. "It's not normal not to hear. Hearing is what makes us happy in our relationships. If you can't hear, you stop talking."

Improved sensory perception won't stop the progression of dementia caused by Alzheimer's disease, experts said, but increasing the ability to hear will help reduce a patient's loneliness and confusion.

The staff at Smith Village, a continuing-care retirement community in Chicago's Beverly neighborhood, said it has noticed increased participation among residents who address their hearing problems.

"Getting hearing aids does help them," said Diane Morgan, memory support coordinator. "When their hearing is down, they experience paranoia or anxiety because they can't hear what's being said to them."

Fisher, whose father suffered hearing loss at an early age, said she began noticing in 2008 that when her dementia patients were fitted with hearing aids –– especially deep-insert hearing devices that remain in the ear for three months at a time –– they socialized more and their memories improved.

In a study released this year, researchers at Johns Hopkins Medicine and the National Institute on Aging found that seniors suffering from hearing loss were more likely to develop dementia over time than those who retain their hearing. Among other things, the research suggests that hearing loss could lead to social isolation, a risk factor for dementia.

The research should offer hope to physicians treating dementia patients, said Dr. Marsel Mesulam, director of the Cognitive Neurology and Alzheimer's Disease Center at Northwestern Memorial Hospital and Northwestern's medical school.

"Doctors and health care providers treating elderly patients should not throw up their hands treating dementia," Mesulam said. "They can look at other factors that are treatable, like hearing loss or vision."

Alzheimer's is the most common form of dementia, a term used to describe the common symptoms of memory loss and declining cognitive abilities that interfere with daily life, according to the Alzheimer's Association. The disease accounts for 50 to 80 percent of dementia cases. Other causes of dementia include brain injuries, infections and tumors, and vascular, Parkinson's and other diseases that affect neurological function.

Nancy Rainwater, a spokeswoman for the Greater Illinois Chapter of the Alzheimer's Association, said that at the very least, a person's hearing loss might cause caregivers to assume there is dementia when there is not.

Naperville resident Debby Berger began taking her 86-year-old mother to Hearing Health Center last year. At the time, her mother's memory had declined. Since she has been fitted with deep-insert hearing devices, her memory has improved.

"Now that she can hear, if you tell her something, she remembers it," Berger said.